Previously, many types and styles of discs have been used in endeavoring to provide an effective means to sort materials classified by size in a rotating screen.
The prior art listed below did not disclose patents that possess any of the novelty of the instant invention; however the following U.S. patents are considered related:
U.S. Pat. No.InventorIssue Date4,795,036WilliamsJan. 3, 19895,450,966Clark et al.Sep. 19, 19955,799,801Clark et al.Sep. 1, 19986,076,684BollegraafJun. 20, 20006,149,018Austin et al.Nov. 21, 20006,318,560 B2DavisNov. 30, 20017,004,332 B2DavisFeb. 28, 2006
Clark et al. in U.S. Pat. No. 5,450,966 teach a disc screen for classifying material by size which consists of a frame with a plurality of shafts mounted parallel with a first stage having discs in a coplanar row. Each disc has a perimeter shaped to maintain the space therebetween during rotation. A second stage includes discs shaped to maintain the space constant.
U.S. Pat. No. 5,799,801 issued to Clark et al. teach a disc screen for classifying material by size which includes shafts mounted on a frame with discs mounted in a row. Each disc is shaped to maintain a space between other discs during rotation. Debris materials are dropped from a roll over section so that the debris either falls vertically or flips over promoting separation. A discharge section agitates the debris while moving up an incline until the larger debris discharges at the rear end.
Bollegraaf in U.S. Pat. No. 6,076,684 discloses a waste paper sorting conveyor having a bed formed by a row of rotatable shafts carrying mutually spaced impellers. The impellers have contours spaced between mating shafts.
Austin et al. in U.S. Pat. No. 6,149,018 teaches a compound disc to eliminate a secondary slot normally formed between adjacent shafts of a material separation screen. The disc includes a primary disc joined to an associated secondary disc. The primary disc and secondary disc are formed of rubber and have the same shape but the secondary disc has a smaller outside perimeter and is wider. The discs are interleaved with oppositely aligned adjacent shafts.
U.S. Pat. No. 6,318,560 B2 issued to Davis is for a disc screen apparatus for separating mixed recyclable materials of varying sizes and shapes. The screen has an enclosure with an input location, a discharge location and a sorted paper location. A first plurality of shafts and second plurality of shafts are located on the frame with one or more motors rotating the shafts. Each shaft includes discs substantially square in shape with radiused corners having a texture, such as ridges. Each disc is assembled about each a shaft from two identical portions which are clamped together about the shaft to form the disc. If the disc is damaged or worn it may be removed from the shaft without disassembly of the shaft from the apparatus or the removal of other discs. The discs are also disclosed as comprising an inner rived frame supporting an outer softer material. This patent of Davis is the basis of the instant invention improvement of a new and novel disc for use with the same or similar apparatus.
Davis in U.S. Pat. No. 7,004,332 B2 discloses an apparatus for classifying a stream of mixed recyclable materials of varying sizes and shapes having an inclined fixed first disc screen section and an articulating section angled section. The angle can be adjusted with a hydraulic cylinder. The frames have complementary mating surfaces that limit the range of articulation of the second disc screen section.
For background purposes and as indicative of the art to which the invention is related reference may be made to the remaining cited patent issued to Williams in U.S. Pat. No. 4,795,036.